As is known, the starch contained in starch-containing raw materials, especially cereals and maize grains, must be made accessible by sufficiently crushing the grains. Therefore, it is necessary and usual to subject these raw materials previously to grinding. This dry grinding of grainy starch raw materials to form a fine flour involves a high expenditure of energy. Thus, for example, rough-grinding of maize grain on a hammer mill requires about 10 kw per metric ton. To grind whole grain on a Hurrican mill to form a fine flour (smaller than 60 mesh), about 60 kw per metric ton are required. Wet grinding of whole, non-steeped grains or larger fragments does not give an economy of energy as compared with dry grinding processes. The direct gelatinization of coarse grits requires very long liquefaction or saccharification periods and additionally results in reduced yields of alcohol.